<!DOCTYPE html>
<html>
	<head>
		<meta charset="UTF-8" />
		<title>Document</title>
	</head>
	<body>
		<script type="text/javascript" >

			class Person {}
			Person.prototype.b = 200

			class Student extends Person{
				name = 'tom'
			}
			Student.prototype.a = 100  //a想给s用

			const s = new Student()
			
			console.log(s.b)
		</script>
	</body>
</html>